#!/usr/bin/env node

const { Readable } = require ('stream');
class MyReadable extends Readable{

  constructor(){
    super();
  }
  _read(){
 
    this.push(String.fromCharCode(this.#c++));
    if(this.#c>'z'.charCodeAt(0)) this.push(null);

  }
#c='a'.charCodeAt(0);
}
let rs = new MyReadable();

rs.pipe(process.stdout);
